feat(API): 견적-주문 연동 필드 및 마이그레이션 추가

- Order, OrderItem 모델에 견적 연동 필드 추가
- Quote 모델에 order_id 관계 추가
- QuoteService 개선
- 관련 마이그레이션 파일 추가

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/Services/Quote/QuoteService.php

@@ -2,6 +2,8 @@
 
 namespace App\Services\Quote;
 
+use App\Models\Orders\Order;
+use App\Models\Orders\OrderItem;
 use App\Models\Quote\Quote;
 use App\Models\Quote\QuoteItem;
 use App\Models\Quote\QuoteRevision;
@@ -369,7 +371,10 @@ public function convertToOrder(int $id): Quote
         $tenantId = $this->tenantId();
         $userId = $this->apiUserId();
 
-        $quote = Quote::where('tenant_id', $tenantId)->find($id);
+        $quote = Quote::where('tenant_id', $tenantId)
+            ->with(['items', 'client'])
+            ->find($id);
+
         if (! $quote) {
             throw new NotFoundHttpException(__('error.quote_not_found'));
         }
@@ -378,19 +383,69 @@ public function convertToOrder(int $id): Quote
             throw new BadRequestHttpException(__('error.quote_not_convertible'));
         }
 
-        return DB::transaction(function () use ($quote, $userId) {
-            // TODO: 수주(Order) 생성 로직 구현
-            // $order = $this->orderService->createFromQuote($quote);
+        return DB::transaction(function () use ($quote, $userId, $tenantId) {
+            // 수주번호 생성
+            $orderNo = $this->generateOrderNumber($tenantId);
 
+            // 수주 마스터 생성
+            $order = Order::createFromQuote($quote, $orderNo);
+            $order->created_by = $userId;
+            $order->save();
+
+            // 수주 상세 품목 생성
+            $serialIndex = 1;
+            foreach ($quote->items as $quoteItem) {
+                $orderItem = OrderItem::createFromQuoteItem($quoteItem, $order->id, $serialIndex);
+                $orderItem->created_by = $userId;
+                $orderItem->save();
+                $serialIndex++;
+            }
+
+            // 수주 합계 재계산
+            $order->load('items');
+            $order->recalculateTotals();
+            $order->save();
+
+            // 견적 상태 변경
             $quote->update([
                 'status' => Quote::STATUS_CONVERTED,
+                'order_id' => $order->id,
                 'updated_by' => $userId,
             ]);
 
-            return $quote->refresh()->load(['items', 'client']);
+            return $quote->refresh()->load(['items', 'client', 'order']);
         });
     }
 
+    /**
+     * 수주번호 생성
+     * 형식: ORD-YYMMDD-NNN (예: ORD-260105-001)
+     */
+    private function generateOrderNumber(int $tenantId): string
+    {
+        $dateStr = now()->format('ymd');
+        $prefix = "ORD-{$dateStr}-";
+
+        $lastOrder = Order::withTrashed()
+            ->where('tenant_id', $tenantId)
+            ->where('order_no', 'like', $prefix.'%')
+            ->orderBy('order_no', 'desc')
+            ->first();
+
+        $sequence = 1;
+        if ($lastOrder) {
+            $parts = explode('-', $lastOrder->order_no);
+            if (count($parts) >= 3) {
+                $lastSeq = (int) end($parts);
+                $sequence = $lastSeq + 1;
+            }
+        }
+
+        $seqStr = str_pad((string) $sequence, 3, '0', STR_PAD_LEFT);
+
+        return "{$prefix}{$seqStr}";
+    }
+
     /**
      * 견적 품목 생성
      */